Start with curiosity, not compliments
A compliment about someone's looks as an opening line rarely works. Interest in who someone is does. Ask about something from the conversation or their profile, and respond to what they tell you.
Flirting in a chat is harder than in person: you miss a smile, a look and the tone of someone's voice. At the same time a chat gives you time to think. With these tips you flirt playfully and confidently, without crossing lines.
A compliment about someone's looks as an opening line rarely works. Interest in who someone is does. Ask about something from the conversation or their profile, and respond to what they tell you.
These small things make the difference:
They ask you questions too, reply quickly and enthusiastically, return to earlier topics and make jokes. Then you're doing well. Short, closed answers usually mean there's no click, and that is completely fine.
Flirting is fun as long as it's fun for both. Don't send explicit messages or photos unless the other person clearly asks for it, don't push after a no, and don't ask for a phone number or address straight away. If someone gets pushy with you, simply block them.
If it really clicks, you can both press "Match" on LiefdesKlik. Your conversation is then saved in Messages and you can continue later, without having to swap numbers right away.
Start a conversation with someone new and see if it clicks.